This program project brings together an interdisciplinary team of three scientists with unique expertise to functionally target and inhibit human polyomavirus infections. The polyomaviruses in general, and the human polyomaviruses in particular, have been shown to utilize distinct host cell carbohydrates and proteins to infect target cells and tissues. The human polyomavirus JCV is the causative agent of a fatal central nervous system demyelinating disease known as progressive multifocal leukoencephalopathy (PML). The majority of PML cases occur in patients with AIDS but recently PML has also been shown to occur in multiple sclerosis patients being treated with potent immunomodulatory drugs that inhibit immunosurveillance of the CNS. There are currently no drugs in the pipeline that target the virus directly and a major goal of this program is to identify compounds capable of directly inhibiting virus infection. This goal will be accomplished by close collaborative interactions between a team consisting of a polyomavirologist, a structural biologist, and a molecular geneticist/virologist. Project # 1 led by Professor Thilo Stehle will focus on structuraly characterizing and identifying sites on the virus that are critical for interacting with host cell surfaces. Project # 2 led by Professor Walter Atwood will introduce site-specific mutations in the virus based on these structures and functionally characterize the mutants. Project #2 will also further develop a drug lead identified in years 1-4 of this program project. Project # 3 led by Dr. Dan DiMaio will conduct genetic screens for factors that are critical for JCV invasion of host cells. The projects will be supported by a virus and pseudovirus production core at Brown University headed by Dr. Gretchen Gee. An administrative core will be housed at Brown University. The overall goal of this program is to use structural information and high throughput genetic screens to identify factors and targets that can be exploited to inhibit polyomavirus infection. The three major investigators on the team have built a strong working collaboration that is evidenced by the solid preliminary data and numerous joint publications that support this application.